Cigarette filters known today generally contain polysaccharide derivatives, either of natural origin or thermoplastic, polyesters, such as polyethylene and polypropylene terephthalate. Patents EP 434332 and EP 434339 of RJ. Reynolds Tobacco Cie describe such filters, they may also contain dried tobacco grains. The use of salts, acids, bases, surfactants in a medium with a basic pH, is mentioned in these various patents.
More specifically against carcinogenic substances, patent WO 96/00019 describes a cigarette filter enriched with Fe++, Cu++ or Mg++ ions. The purpose is to retain free radicals and especially protect metalloproteins.
Patent WO 96/10929 describes an inhibitor of free radicals, such as an O-alkylated derivative of 2,4-monofurfurylidene sorbitol, associated with an antioxidant, the action of which is to filter polycyclic aromatic hydrocarbons (PAH), mainly 3,4-benzo-(a)-pyrene (BaP) with known carcinogenic potency.
Moreover, it is known that fluorine has antitumoral effects. Notably, it is involved in the composition of dexamethasone and 5-fluorouracil. Further, the use of laboratory polytetrafluoroethylene (PTFE) filter paper is known.